Injection device for combustion engines



Dec. 17, 1940., J. M. R. RETEL 2,225,019

INJECTION DEVICE FOR COMBUSTION ENGINES Filed Jan; 8, 1956 2 Sheets-Sheet 1 Fig.1

a/m m- .40 K 6m Dec. 17, 1940. J. M. R. RETEL V INJECTION DEVICE FOR COMBUSTION ENGINES Filed Jan.- 8, 1936 2 sheeps-sneet 2 Patented Dec. 17, 1940 t t 2,225,o19 nrsorronn'avrcn non COMBUSTION memes I rule Ben Betel, Neuilly-sur-Seine, France The present invention relates to pumps for the injection of a certain-amount of liquid fuel into the cylinders of internal combustion One of the objectsv of the present invention is to provide a pump of this type inwhich the time at which injection is startedis variableaccording to the charge-of fuel to thfid of revolution of they engine,. so-as toobtainan advantageous working of said-engine forany charge and any speed of revolutionthereof. p ,7

Another object of the present inventionis to provide a pump of the kindabovereferred to in which the position of ,the organ controllingthe beginning of injection depends, for a :given amount of fuel injected, uponthes ed of revolution of the engine. V i I Other 'featuresof the present inventionwill result from the followingdescription; of; some specific embodiments thereof.,,;-

Preferred vembodiments of the presentinvention will be hereinafter described withreference to the accompanying drawings, given merely, by way of example andinwhich:

Fig. 1 is an axial sectionalviewfofeaiem- ,25 bodiment of the invention; Fig.- 1? shows armedification; Fig. 2 is a tran'sversesectional; view of -said pump on the line II]I otFig. 1; s

Fig. 3 shows, on enlarged-scale, aydetailof so th pu p f s-r andiz; a; Fig. 4 shows a modificatiOn. of; the detail .illusr d y Fi Fig. 5 is an axialsectional view of,v a secondembodiment; 3

still another o i n -1. r In the embodiment of Fig. :1; the cylinder ;,l of the pump fits in a bore-provided in a block 2 thebottom of which is:'fixed to casingj. p-This o casing contains an oil ba h ,for a shaftllv driven inorderto balance th 4 Y a w o i en i JP... w. 4

Jim

' f Application 8, 1936, Serial No. 58,204

L ,JnFi-ance January 11, 1935 *f' z claims. (Cl. 123-139) 3, the transverse edges of recess l2 are oblique with respect to the axis of piston 9, while the corresponding edges of recess I3 are at right angles to said axis.

The upper end of cylinder I is closed by a 5 plunger l4 subjected'to the action of a return spring l5, which is housed in the screwed cap l6 of block 2. Plunger I4 is provided with a. head I40 which, in the position of rest bears upon an annular member ll, of well determined thickness. 10

Cylinder l is provided with a delivery conduit I8 connectedto the injector (not shown in the drawings) through a conduit l9, under the control of check valve 30. The orifice of this passage I8 is uncovered when the upper edge of the 15 recess i2 of piston 9 moves past said orifice, in the upward movement of said piston.

Three other passages 2|, 22, and 23 provided in cylinder I open into a chamber 24 provided in block 2, said chamber being connected to a fuel 2 tank (not'shown in the drawings). Passage 22 is the suction passage of the pump. It is intended to cooperate with the upper edge of piston 9. Passage 2| is a leakage conduit, placed under the control of plunger i4. Passage 23 is also a leak- 25 age conduit, the orifice of which is controlled by the upper edge of the recess I3 of piston 9. The lower part of said piston is provided with parallel flat faces 25, fitting against corresponding flat faces provided in the inner surface of a sleeve 26 capable of rotating freely with respect to the lower part, of reduced diameter, of cylinder I,

and prevented from moving in the longitudinal ,direction.

teeth 21 located above sleeve 1. These teeth are in mesh with a rack 28, screwed on a. rod 29 extending transversely to piston 9 and movable in the direction ofits own axis.

If,.as shown by Fig. 2, the pump includes a plurality of pistons, there is one rack 28 for each ;-piston.

circular grooves of the desired profile formed in the periphery thereof, with flat faces v.3 1), cut at from one another, and, close to one end, other flat faces 3|, making an angle of 5 5 fiqff with the first mentioned flat faces 30. This arrangement of racks 28 screwed on a rod 29 it possible to accurately adjust the relat yenposition of said racks on said rod.

Sleeve 21 is provided with external Each of these racks consists of a cylinder e1 flat faces 30, 3| above mentioned facilitate 5o th operation of adjustment, which is performed y means of a spanner. Once the racks have been adjusted in a predetermined. position, they are ented from moving out of adjustment by a plug 32, having a flat face parallel to 5 one of the faces 30 above mentioned and located close thereto.

The axial position of rod 29 is adjustable axially, through a lever 33. The latter acts on push piece I33, which in turn controls the displacements of rod 29, through a spring 34. At the opposite end of rod 29 there is provided a push piece 35 which permits of brin in the engine into idling working, without acting on lever 33, owing to the provision of spring I4. The displacement of rod 29 is limited in this direction by stop ring 36, the position of which is variable in order to permit of adjusting the idling.

It may also be desired to bring the engine into idling working when it reaches a predetermined speed of revolution. I may, for instance, for this purpose provide a for]: 38 adapted to act on a collar 31 of rod 29, said fork being controlled by a centrifugal governor (not shown in the drawings) operated by the engine.

The control of the injection is effected in the following manner:

Piston 9 exerts a compression on the liquid fuel when the upper edge of said piston covers passage 22. The fuel lifts plunger I4 until the latter uncovers the orifice of the upper passage II. The upper edge of the recess I! of piston 9 then uncovers the orifice of the passage it leading to the injector. Injection takes place, while plunger I4 is moving back toward its stop II. It lasts until the upper edge of the recess I3 of piston 9 opens the orifice of the lower by-pass conduit 23.

In view of the fact that the active edge of recess I2 is inclined, it is quite clear that the time at which injection starts depends upon the angular position of piston 9 about its axis, which position can be manually adjusted, according to the charge of fuel to be supplied to the engine. On the other hand, the time that elapses between the time of opening of the orifice of passage It and the time of opening of by-pass pasage 23 depends upon the speed of revolution of the engine.

For a given charge to be supplied to the engine, it is necessary to turn piston 9 about its axis, in. the direction that corresponds to earlier injection, through an angle which is the greater as the speed of revolution of the en ine is the higher. The advance to injection therefore depends both upon the speed of revolution of the engine and upon the charge of fuel.

In order to obtain a higher sensitiveness of the device at small speeds of revolution, and a more considerable lead to injection for high speeds and charges, I may, as shown by Fig. 4, give the active edge of recess II, a double angle of inclination, -40, the smaller inclination corresponding to small charges of fuel. The active edge of recess It may also be made more orless oblique with respect to the axis of piston 9.

In the embodiment of Fig. 5, the passage ll through which fuel is fed to the injector is provided at the upper end of the cylinder. It is controlled merely by check valve 20. The inlet passage 22 is controlled by the bottom of an inclined notch 4i starting from the upper edge of piston 9. The axial conduit IQ of the piston pxtends downwardly to the outside of the cylinder and opens at 42 into the outer face of the piston, at the end of a transverse branch. Orifice 42 cooperates with a sleeve 43, adapted to turn freely with respect to the piston and prevented from moving longitudinally with respect to said piston. This sleeve is provided with an aperture 44 the lower edge of which includes a portion oblique with respect to the axis of the piston, between two portions at right angles to said axis.- Sleeve 43 may be displaced longitudinally, for adjustment purposes, by means of nut 45, which is screwed on the bottom of cylinder I, or through the interposition of annular elements 44, the thickness of which varies according to the desired adjustment of the interval between the upper face of sleeve 43 and nut 45.

Sleeve 43 is provided with external teeth 41, in mesh with the teeth of a pinion 48, which is adapted to turn under the action of a centrifugal governor or any other device responsive to the speed of revolution of the engine.

Piston {drives fuel to the injector, through passage It, when the bottom of its notch 4| moves past suction orifice 22. Injection ceases when orifice 42 is uncovered by the aperture 44 of sleeve 43. In this case also, the beginning of the injection depends upon the angular position of piston 9 about its axis. For a predetermined charge to be injected to the engine, this angular position of piston I isitself a function of that of sleeve 43, which in turn depends upon the speed of revolution. The lead to injection therefore depends upon both the charge of fuel and the speed of revolution of the engine.

The same is true for the embodiment of Fig. 6. In this case, the suction of fuel takes place during the forward stroke of piston 8, through orifice 42 which, during the return stroke of the piston, constitutes a leakage orifice, placed under the control of sleeve 43. The upper end of cylinder l consists, in this case, as in the embodiment of Fig. 1, of a plunger l4,'subiected to the action of a return spring Ii. The axial e of piston 9 is provided with a second transverse branch 49, opening into a recess 5| of said piston. The upper edge of this recess, which is inclined with respect to the axis of piston 8 controls the orifice -of the passage It through which fuel is fed to the injector.

The delivery of the pump begins when the leakage orifice 42 comes opposite a solid portion of sleeve 43. It produces an upward movement of plunger H. The beginning of injection takes place when the upper edge of recess 5| uncovers the orifice of passage l8. Injection ceases when piston l4 has come back against its seat.

All the pumps according to these embodiments automatically stabilize the speed of revolution of the engine. This is due to the fact that, when this speed tends to increase, sleeve 43 moves in the direction which corresponds to a decrease of the amount of fuel injected, the reverse action taking place if the speed of the engine tends to decrease (Figs. 5 and 6). Similar effects are obtained with the embodiment of Fig. 1, as g sequence of the variations resulting, for the speed of movement of piston 9, from variations of the speed of revolution of the engine.

With the embodiments of Figs. 5 and 6, it is easy to limit the maximum rate of feed of fuel by longitudinally displacing sleeve 43, through a displacement of nut 45 or by changing the'thickness of annular elements 46.

With the embodiment of Figs. 1 to 4, the same adjustment is obtained by making use of annular members ll of different thicknesses, which modifies the distance between the lower edge of the plunger and the discharge orifice 2| which it uncovers during the delivery of the pump.

In the case of engines intended to run at very high speeds, the arrangement shown by Figs. 1 toimaybemodifiedasshowninliig. 1 sothat,

i I the opening of said deliver-{opening by said at these speeds of revolution, the inclined active upper edge of recess l2, provided in piston 9, uncovers the orifice of passage ll before the orifice of passage 22 has been covered by the upper inclined end of piston 9. This arrangement is shown by Fig. 1'.

orifice of passage 22 is subsequently closed,- sudden rise of the injection pressure. 'I'hisrisagpf pressure may be useful at very high speeds -ln this case, the lead to injection is controlled by the upper edge of piston 9 which is giv n, an

clined shape, as shown at 5| in Fig. 1a..

In a general manner, while I have, in

changes made in the arrangement, disposition, and form of the parts, without departing from the principle of the present invention as comprehended within the scope of the appended claims.

What I claim is:

1. In a pump adapted to work in connection with an internal combustion engine, for the injection of fuel to said engine, the combination of a cylinder, a piston movable. in said cylinder, means for reciprocating said piston in said cylinder, said piston being provided with an axial conduit opening into one end face thereof and into the lateral surface of said piston near the other end thereof, this last mentioned end of the piston projecting from said cylinder and being adapted to be immersed in fuel, a sleeve surrounding said last mentioned end of the piston provided with an aperture having at least one inclined edge adapted to cooperate with the second mentioned opening of said axial conduit of the piston, means for angularly displacing said sleeve in response to variations in the speed of revolution of the engine, a delivery passage in the lateral wall of said cylinder, said piston being provided with a recess having at least one inclined edge adapted to cooperate with said passage and communicating with said axial conduit, a plunger slidable in said cylinder closing the end thereof that corresponds to the first mentioned end of said piston, and elastic means for urging said plunger into said cylinder, and means for adjusting the angular position of said piston about its axis in said cylinder.

2. In a pump operating in connection with an entering the other end of said cylinder, an inlet in the wall of said cylinder controlled by the inner end of said piston, said piston having two cavities in its cylindrical surface, one of said cavities having at least one edge oblique to the generatrices of said piston, passage means between said cavities and the space between said phmger and said piston, a delivery opening adapted to cooperate with the oblique edge of said first mentioned cavity for injection purposes, a by-pass in the wall of said cylinder adapted to cooperate with the other cavity in order to discharge the space between said piston and said plunger so as to stop the injection of fuel, and means for rotating said piston about its axis, the edge of the inner end of said piston being oblique and located at such a distance from the oblique edge of said first mentioned cavity of said piston that said inlet is only covered by said piston after h a di if. description, disclosed what I deem to be practical 1,;

cavity. I v

8. In connection with an internal combustion engine having fuerinjectionmeanaa pump for feeding fuel to injectiom means which comme a- ,c a

The inertia of plunger ll produces, whe the her having a sp ring l, lm eans for forcing to said chambenat be injected atone ative by the engine and onnecting said chammeans fora time nternal "combustion means which comber' ha ving aspring into'said chamber, 'at each stroke of the pump, an amount of fuel greater than the maximum to be injected at one stroke, means, operative by said engine, for connecting, at each stroke, said chamber with said fuel injection means, so as to start injection, means, operative by said engine, for discharging said chamber to the outside, so as to stop injection, a certain time after the starting thereof, said time being inversely proportional to the speed of said engine, and means for adjusting in operation the two last mentioned means so as to permit of varying both the time of starting of injection and the duration of injection.

5. In connection with an internal combustion engine having fuel injection means, a pump for feeding fuel to said injection means which comprises, in combination, a chamber having a spring loaded outwardly yielding wall, means for forcing under a limited pressure into said chamber, at each stroke of the pump, an amount of fuel greater than the maximum to be injected at one stroke, and slide valve means, driven by said engine, for first connecting, at each stroke, said chamber with said fuel injection means, so as to start injection, and subsequently dischargin at a farther point of its stroke, said chamber to the outside, so as to stop injection, whereby the duration of injection is inversely proportional to the speed of said slide valve means and therefore to the speed of said engine.

6. In connection with an internal combustion engine having fuel injection means, a pump for feeding fuel to said injection means which comprises, in combination, a cylinder, a spring loaded plunger forming one end of said cylinder, a piston driven by said engine movable in said cylinder, a port in the wall of said cylinder communicating with a source of fuel adapted to cooperate with the inner end of said piston, a by-pass port in the wall of said cylinder between said first mentioned port and the end of said cylinder fitted with said plunger, for the outflow of the excess of fuel forced between said piston and said plunger, whereby a too large amount of fuel is placed under a limited pressure in said cylinder between said piston and said plunger for each inward stroke of said piston, said piston being provided with two cavities in its cylindrical wall, one of said cavities being nearer the inner end of the piston than the other, said piston being provided with a longitudinal passage opening at one end into its inner end and at the other end into both of said cavities, a delivery port in the wall of said cylinder communicating with said injection means adapted to communicate with n amount of fuel 3 peed ofsaid engine.

1, means for forcing.

the first mentioned cavity, and a discharge port in the wall or said cylinder adapted to cooperate with the other cavity after said first mentioned cavity has come opposite said delivery port.

7. In connection with an internal combustion engine having fuel injection means, a pump for feeding fuel to said injection means which comprises, in combination, a cylinder, a spring loaded plunger forming one end of said cylinder, a piston driven by said engine movable in said cylinder with a reciprocating motion at-a speed proportional to that of said endine, a port in the wall 'of said cylinder communicating with a source of fuel adapted to cooperate with the inner end of said piston, a by-pass in the wall of said cylinder between said first mentioned port and the end of said cylinder fitted with said plunger, for the outflow of the excess of fuel forced between said piston and said plunger, whereby a too large amount of fuel is thus placed under a limited pressure in said cylinder between said piston and said plunger for each inward stroke of said piston, said piston being provided with two cavities in its cylindrical wall, one of said cavities having at least its elhe nearer to 8 the inner end of said piston directed obliquely to the generatrices of said piston, said listen being further provided with a lnlnitudinal pas-3e opening atoneendintoitsinnerendmdat the otherendintohothofsaidcavitigadelivery 10 port in the wall of said cylinder mlmmicaiing with said injection meam M to cooperate with saidflrstmenfloned cavity,adhcharleport inthewalloisaidcylinderedaptedtocooperate withtheothercavityaftersaidmitmmflmed 15 cavityhas come oppositessiddeliveryporgand adjusting meansfor nryinsdnaervicethelngnlarnnpositionofsaidplstonabontitsaxiainaid cy der.

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